Comparison of age determination techniques for known-age Cape fur seals

Known-age teeth were used to validate age determination techniques for the Cape fur seal (Arctocephalus pusillus pusillus). Thin sectioning and staining of decalcified teeth produced the poorest age estimates. For etched half canines, only upper canines could be used to estimate age with good results, and coating improved the accuracy. Scanning electron microscopy produced poor accuracy in age estimation. External ridges reflected age accurately only in younger age classes and should only be used to verify counts of internal growth layer groups, or when rapid, preliminary estimates of age are necessary. This study has highlighted the importance of comparing different age determination techniques and validating such techniques with known-age animals. The reliability with which age can be estimated for the Cape fur seal has also been improved.